Reproducing system for sound on films



June 9, 1936. I 5, c, w M 2,043,871

REPRODUCING SYSTEM FOR SOUND ON FILMS Filed Sept. 27, 1932 INVENTOR. cy t'e/vvamt G, QF/A W MW A TTORNEYS.

Patented June 9, 1936 PATENT OFFICE REPRODUCING SYSTEM FOR SOUND.

ON FILMS Stewart 0. Whitman, New York, N. Y., assignor to Whitman Sound Systems, Ltd., Dover, Del., a. corporation of Delaware Application September 27, 1932, Serial No. 635,120 5 Claims. (Cl.179-'-100.3)

This invention relates to new and useful improvements in the art of recording sound on film and more particularly to reproducing apparatus to accomplish these results. I

An object of this invention is to produce a sound on film'reproducing apparatus which is small, light in weight, and compact.

Another object of the invention is to produce a reproducing apparatus which is provided with means for operating in conjunction with film having a single line of sprocket holes.

A further object of the invention is to provide a sound take-off device which eliminates scratching, stretching and uneven motion of the Still another object of the invention is to provide a sound take-ofi apparatus in which the distance between exciter lamp and photocell is comparatively very short.

With these and numerous other objects in view, my invention consists in the novel features of construction, combination and arrangement of parts as will be hereinafter referred to: and more particularly pointed out in the specification and claims.

In the drawing, forming a part of this application:

The figure represents a side elevation of the device, partly in section, and with parts broken away.

' The elements in the drawing and their various arrangements will be more particularly described in the disclosure which follows.

The use of 16 millimeter film for sound recording having a single line of sprocket holes and a wide sound track is desirable because of the greatly improved sound track obtainable. The present invention relates to a simple, reliable and compact reproducing apparatus for this film.

By the use of a straight filament exciter lamp a single, short optical reduction lens system'may be used. The method of carrying the film past the exciter light, the method of transmitting said light through the sound record on the film, and the method of picking up the transmitted light by the photocell constitute the subject matter of this invention. 7

Referring to the drawing the numeral I designates the exciter lamp and number 2 the reduction lenses. The film 3 passes around an idler pulley 4 which is of special design. In most sound film reproducers the sound track on the film is exposed to the exciter light while passing over a stationary gate and is held in contact therewith by friction shoes or rollers. This method results in film wear, scratches, stretching, and, most important, uneven motion. In the present apparatus these objectionable features are eliminated by the special pulley 4. This pulley is flanged on the side opposite the sound track, as shown at 5, and is sufliciently narrow to allow the sound track to project beyond the edge of the pulley opposite the flange. The manner in which the film projects beyond the pulley can be seen at 6 on the drawing. Thus it can be seen that no sliding friction is encountered while the film is passing theexciter light, and all wear, scratching, stretching, and uneven motion is eliminated. The pulley 4 is preferably slightly tapered wider toward the flanged edge. This causes the edge of the film carrying the sprocket holes to ride at all times against the inside face of the flange thus preventing any lateral motion of the sound track while passing the exciter light. The pulley 4 is free to rotate and is frictionally driven by the film. The film driving means (not shown) may be of any standard type except that the drive sprocket must be provided with but a. single row of sprocket teeth to accommodate the single row of sprocket openings 6a in said film.

' The pulley shaft 1, rotating in the bearing 8 in order to restrict the width of the light beam to the width of the sound track. The complete assembly effects a saving in space and weight not heretofore possible. In addition, due to the use of film having the single row of sprocket holes, smoother and quieter sound pick-up is effected and the advantage of the wide track is obtained.

As shown in the figure, the exciter lamp I has a rectilinear filament I4 which is mounted substantially parallel to and in register with the aperture I3 in light screen I2 and to the breadth of sound track 6, and the striations of the record thereon. An incandescent lamp with a rectilinear filament is shown in the Hart Patent No. 1,588,886, but the arrangement shown by Hart is not adapted to be employed for the purpose which I disclose. My rectilinear filament should be distinguished from a cylindrical helix filament as shown for instance in the Hardy Patent Number 2,010,951, which helicalfilament is not adapted toconstitute an efiicientlight source to attain the results which I have set forth. 7 Having thus described the invention what is claimed is:

1. Ina system for reproducing sound from film,

'a source of light comprising a rectilinear filament V 1 exciter lamp, an idler pulley, a film carrying 2.

soundtrack on one edge thereof passing over and frictionally engaging said pulley, said pulley being flanged'on one end, said film being widerr than the face of said pulley by the width of said sound utrack and being so positioned that said sound 7 larger at the flanged end'thereof, an'opaque plate disposed betweensaid source and said film and beingapertured over the sound track on said film,

t jecting soundtrack on said film on the side theretrackprojects beyond the unflanged end of said pulley when the edge of said filmnot carrying the sound track abuts theflange of said pulley, the diameter of said pulley being tapered slightly and'a light sensitive cell mounted under 'the pro- "of opposite said light source, said rectilinearffllamerit being mounted substantially. parallel'to and inlregister with the aperture insaid plate and the breadthof said soundtrack. I,

f '2.In a system for reproducing sound from film, j

, a source of light comprising a rectilinear filament'exciter lamp, an*idler pulley; a'film car-1 rying'a sound track passing; over and friction-1 allyc rengagingj said pulleygsaid pulley being flanged on one end, the'surface of said pulley being slightly conical and being tapered wider at the flanged end, an opaque plate' disposed between said source and said 'film'and being a'pertured over the soundtrack on said film, and fa light sensitive, cell 7 mounted adjacent said film'on the side thereof opposite said light source and under-said sound track, said rectilinearfilament being mounted substantially parallel to and in register with the aperture in said plate and the V breadth ofsaid' sound track.

3; In 'a system forreproducingsound from'film, V angntso rce comprisinga rectilinear filament exciterlamnan idler pulley, a'film carrying a f sound track on one edge thereof passing overand 'frictionally engaging said pulley, said pulley bei in'g flangedonthe end opposite the end carryi so 7 V r at the flanged end, the faceof said pulley being narrower than said film by the width of said ing the sound track, thesurface of said pulley being slightly conical and being tapered wider sound track, an opaque plate disposed between said source and said film and being apertured over the portion of said film carrying said sound track and projecting beyond the unflangedend of saidpulley, and a light sensitive cell on the side of said filmopposite said source and in register with said sound track, said rectilinear filament being 5 I mounted substantially parallel to andin registerwith the'aperture in said plate and the breadth of said sound track. N r 4. In a system for reproducing sound from film,

a light source comprising a rectilinear filament l exciterlamp, an idler pulley, a film carrying a sound track on one edge thereof passing-over and V l frictio'nally engaging said idler pulley, said film having sprocket holes only on the edge thereof which does not carry the sound track, said pulley 1 being flanged on the end carrying the sprocket 7 holes insaid film, the surface of said pulley being slightly conical and beingtapered wider at the "flanged end, an independent drive sprocket providedwithteeth on only one side to engage the sprocket holeson one edge or said film, the face of said idlerj pulleybeing of such width that when the edge'of the film carrying sprocket holes abuts v the flange of said pulley, the sound track on said film-projects beyond the 'otherendof said pulley, an opaque plate disposedbetween said source and said film, andibeing apertured over said sound track and a light sensitive cell on the side of said film opposite said source and in register with said sound track, said rectilinear filament being mounted substantially parallel to and in register withrthe aperture in said plate and the breadth of; 7

said sound track.

" 5. Inia system for reproducing sound irom'i'llm, V

asource of, light comprising a rectilinear filament exciterv lamp, a rotatable shaft; an idler pulley I 1 carriedion said shaft,",a film carrying a sound track: 7 passing over and frictionally engaging said pulley,

said pulley being flanged on' one end, the surface r of said pulley being slightly conical and being tapered wider at the flangedend, an opaque plate disposed between said source and said film, and being apertured over the soundtrack on said mm,

alight sensitive cell mounted adjacentsaid film' s'rEwAR'rC, WHI'I'MV AN, I 

